Answer:
Let us assume the total number of students surveyed = x
Then
Number of students preferring red = x/4
Number of students preferring blue = x/8
Then
Number of students remaining = x - [(x/4) + (x/8)]
=x - [(2x + x)/8)
= x - (3x/8)
= (8x - 3x)/8
= 5x/8
Number of students preferring the color green = (3/5) * (5x/8)
= 3x/8
We also know that the total number of students preferring the color green is 15
So
3x/8 = 15
3x = 15 * 8
x = (15 * 8)/3
= 5 * 8
= 40
So in total 40 students were surveyed. I hope the procedure is clear to you.
Step-by-step explanation:
Work backwards with pythagoras' theorem:
c^2=a^2+b^2
Here, a and b both equal to x. Therefore, you can write this as 8^2=2x^2. So 64=2x^2. Sqrt on both sides to give you 8=2x, hence x=4. However I must warn you that this working out may have a flaw, as I found that x actually equals to 5.66
